Process of finishing electric conductors



A ril 13, 1943. c. EATON PROCESS OF FINISHING ELECTRIC CONDUCTORSnyaomzou FMKUdQu u math-mm W Z L waommm ZPEm Mai: hzim 63m Filed April21, 1939 FM v I I, M 1 ym c aw g w MH, .m Ms W? 1 y IO AH, I. J \aPatented Apr. 13, 1943 rnocsss or rmsnmcsnscraro coNnUc'rons Irving C.Eaton, Nichols, Coma, assignoi' to General Electric Company, acorporation oiNew York Application April 21,1939, ,serial No. 269,280 TClaims. "(01.117-92) v g r the wire is run continuously withoutanyjinter- My invention relates to a process for applying a finishingcoating to insulated conductors, and more particularly to a process forcontinuously applying a' moisture-resisting, flame-retard'ing andcolored finish to insulated conductors, for example, building wire. I

According to former processes such finishes were applied in individualsteps, and it was necessary'to allow a setting period for each of thecoatingsbefore the applicationoi the succeeding one in order to preventmixing and consequent ruptionirom thesaturating tank to the tankcontaining the flame-retarding compoundand that the stearine pitch isapplied directly over the asphalt. saturant. 1 The stearine pitch ismaintained at temperatures ranging from approximately 300 F. to 325 F. v

Upon passage 01' thejacketed conductor from the'tank of flame-retardingcompound, the excess loss of desirable properties such "as flameresistance. Thismeant'a considerable loss in time in finishing theconductor and an increase in cost due to the numerous handlingoperations incident to'carrying out the individual steps in applying thefinishing coats.

The object of my invention is the provision of a new and improvedprocess whereby the moistum-resisting, flame-retarding and coloredfinishes may be applied continuously on after the other without anyinterruption. in the-treatment oi the insulated conductor. 1 I I In theaccompanying drawing, Fig. l-shows an assembly of apparatus whichpermits, carrying out my continuous process; and Fig. 2 is a view of aninsulated conductor finished in accordanc with my process.

In accordance with my invention, an insulated conductor I0 is subjectedto a continuous finishing process and is unwound continuously from atake-oi! capstan II and after being subjected to the various finishingprocesses is wound up on a take-up capstan II. The conductor I0 isprovided with any convenient jacket of insulating material, for example,a fibrous insulating material such as cotton braid.

The insulated conductor passes over a guide pulley l2 and is then woundseveraltimes around a saturating reel or drum mounted in a saturatingtank H. The tank I4 contains a moistureresisting compound I 5, forexample, a bituminous compound containing asphalt; By being passedseveral times around the drum l3, the jacketed wire isimmersed in thesaturant for a time interval sufllcient to thoroughly impregnate thefibrous covering with the bituminous compound. The moisture-resistingcompound should be applied at a temperature of approximately 350 F.

'After passing the wire through the moistureresisting compound th excessmaterial is removed by means of a wiper l8 and the wire is then guidedby means of the rollers l! to a tank I I6 containing a flame-retardingcompound 10, for example, stearine pitch; It should be noted thatmaterial is removed by a wiper 20 andthe coated dered material '22, forexample, talc and isthen wound around a drivingcapstan 23. A wiper 24removes; excess tale. The powdered talc forms-a fine protectivesurfaceand prevents the-coated jacket from sticking to the drivingcapstan. 'If desired, the talc coating may be omitted without in thleast ailecting the quality of the finished product, for example, if thedriving capstan is omitted.

r The coated conductor passes from the driving capstan to a tank,containing a quantity of paint 28 which is applied directly over thecoatings oi flame-retarding and moisture-resisting compounds. I employ aquick drying paint using synthetic resins having solvents miscible withwater, for example, a chlorinated rubber paint.

Excess quantities of the paint. ar removed by a.

travels backand forth through the water bath' several times and thenpasses'out oi the tank through an air blast 3| which removes the excesswater from the conductor and dries it. Fresh water is circulated throughthe tank 28 continuouslyby means of the inlet and outlet pipes 32 andlast the temperature from which it comes from thewater supply.

One purpose of the water bath is to dry the paint. This is accomplisheddue to the fact that the paint contains a water soluble solvent, andthis solvent is removed from the paint as the conductor passes back andforth through the water bath permitting the pigment to dry on the wire.

In addition 'to drying the paint, the water bath A cools the wire whichhas been heated by the hot wire or adhesion between the adjacentcoatings of the wires.

In some instances it may be desired to print or mark the building wirefor the purpose of identifying the size of the wire or the source ofmanufacture. In such cases the wire is passed directly from the waterbath through a printing machine 33 where any suitable identificationmeans may be applied to the painted wire. The printing is done with acolored ink contrasting with the color of the paint coating.

After being printed the wire is passed over a guide pulley 34 to a tank35 containing wax or paraflin 36 which provides a slick finished coatingon the painted wire. The'wax provides, a smooth satin finish for thewire and gives the wire a fishable outer coating making it particularlyadapted for drawing within a metallic conduit. A wiper 31 removes anyexcess wax or paraflin as the wire is wound around a driven capstan 38before being coiled on the take-up.

capstan II. The wax or paraflln is applied at a temperature ofapproximately 160 F. In those cases where the wire is not printed theouter slick finish of wax or parailin is applied directly over thepaint.

According to my invention, the wire is run continuously through themoisture-resisting and flame-retarding compounds without the necessityof interrupting the process to permit the setting of each of theselayers of compounds prior to application of theother, such as was thecase according to former practices. This is due to the fact that thewire is impregnated at a speed such that the water bath 29 cools thewire before the flame-retarding and moisture-resisting compounds havehad an opportunity to intermix such as might destroy the efiectivenessof the flame-- retarding compound. Unless intermixing of these compoundsis prevented, the coatings willbecome sticky and the conductor will notpass the flame test for flame-retarding finishes. By applyinga painthaving a water soluble solvent immediately over the flame-retardingcompound and then removing the solvent by means of a water bath, it ispossible to paint directly over the flame-retarding compoundwithout thenecessity of setting this compound prior to application of the pantbecause the water bath not only drieskthepaint but cools the wirepreventing intermixingb! the paint and flame-retarding compound.Moreover, the use or a paint of the type mentioned in combination withthe water bath makes it unnecessary to interrupt the processto permitdrying of the paint prior to application of the finishing wax, such aswas thecase according to former practices, when it was necessary to passthe painted wire through a drying chamber before application oi thefinishing wax. In painting over the impregnating compounds, any suitablecolored paint may be employed including the light colored paints which,it has been found, are very effective in covering the black coloredimpregnating compounds. v

The conductor is run continuously through the various finish coatingswithout the needot intermediate setting steps such as would necessitatespecial handling. For a No. 14 wire, the conductor may be subjected tothe finishing process at speeds of approximately 1'75 to 275 feet perminute. The process results in a conductor having an excellentmoisture-resisting and flame-retarding finish and one on which the paintwill not peel or flake off upon twisting or bending of the conductor.

What I claim as new and desire to secure'"-b Letters Patent of theUnited States is:

1. The process of treating the insulating jacket of an electricconductor which comprises apply} ing a hot layer of moisture-resistingcompound including bituminous material to said jacket, applying a hotlayer. of flame-retardng compound immediately over saidmoisture-resisting compound, applying a coating of paint having a watersoluble solvent over said flame-retarding compound and then immersingsaid jacket in a water bath to dry said paint and to cool said layers toprevent blending of said compounds.

2. The process of treating the insulating jacket of an electricconductor which comprises applying a hotv layer of bituminous saturantto said jacket, applying a hot layer of stearine pitch, applying acoating of paint having a water soluble solvent, and then immersing saidjacket and layers in a water bath t0 dry said paint and simultaneouslycool and prevent blending of said layers of bituminous saturant andstearine pitch.

3. The process of treating the insulating jacket of an electricalconductor'which comprises applying a hot layer of moisture-resistingcompound to saidjacket, applying a hot layer oi flame-retarding compoundincluding ,stea'rine pitch immediately over said moisture-resistingcompound, applying a coating or paint having a water soluble solventover said flame-retarding compound and then immersing said jacket in awater bath to dry said paint and to cool said layers to prevent blendingof said layers.

, 4. The process of treating the insulating jacket of an electricalconductor which comprises applying a hot layer of moisture-resistingmaterial to said jacket,applying a hot layer '01 flame-retardingcompound immediately over said moisture-resisting compound, applying acoating of paint having a water soluble solvent over saidflame-retarding compound, andthen immersing said Jacket in a water bathto remove said solvent todry said paint and' to cool said layers toprevent blending of said material and compound.

5. The process of treating the insulating jacket of an electricalconductorwhich comprises applying a hot layer of bituminous saturant tosaid Jacket, applying a hot layer of stearine pitch immediately oversaid asphalt 'saturant, applying a coating of paint having a watersoluble solvent immediately over said stearine pitch, immersing saidjacket and layers in a water bath to remove said solvent and dry saidpaint and simultaneously-cooled to prevent blending of said layers ofbituminous saturant and stearine. pitch and then applying a coating ofwaxlike material over said paint to provide a slick finish to saidconductor.

- IRVING C. EATON.

